1. Field
Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to construction of a long training field (LTF) sequence within a preamble.
2. Background
The Institute of Electrical and Electronics Engineers (IEEE) 802.11 Wide Local Area Network (WLAN) standards body established specifications for transmissions based on the very high throughput (VHT) approach using a carrier frequency of 5 GHz (i.e., the IEEE 802.11ac specification), or using a carrier frequency of 60 GHz (i.e., the IEEE 802.11ad specification) targeting aggregate throughputs larger than 1 Gigabits per second. One of the enabling technologies for the VHT 5 GHz specification is a wider channel bandwidth, which bonds two 40 MHz channels for 80 MHz bandwidth therefore doubling the physical layer (PHY) data rate with negligible increase in cost compared to the IEEE 802.11n standard.
A VHT Long Training Field (LTF) is a part of a transmission preamble, and can be utilized at a receiver side to estimate characteristics of underlying multiple-input multiple output (MIMO) wireless channel. Methods are proposed in the present disclosure to construct the VHT-LTF sequence, while providing a low peak-to-average power ratio (PAPR) at a transmitter side.